Normally, the use of special factory tools is avoided for repair procedures, since these are not readily available for the do-it-yourself mechanic. When it is possible to perform the job with more commonly available tools, it will be pointed out. Occasionally, however, a special tool was designed to perform a specific function and should be used. Before substituting another tool, you should be convinced that neither your safety nor the performance of the vehicle will be compromised.
An example of this is using a piston engine compression gauge to measure cylinder compression in a rotary engine. Conventional piston engine compression gauges will not render the degree of accuracy that is required for rotary engines. With these engines, a special digital compression tester is required to measure the pressure of the three combustion chambers.
Some special tools are available commercially from major tool manufacturers. Others can be purchased from your car dealer. In most cases where a tool is designed for a particular job on a particular car model, and therefore made available through the dealer network. You can usually purchase a similar tool at an automotive parts store or elsewhere. You might want to give the factory part number to not only your dealer, but to other sources, and shop competitively for the item you need.
Special tools are occasionally necessary to perform a specific job or are recommended to make a job easier. Their use has been kept to a minimum. When a special tool is indicated, it will be referred to by the manufacturer's part number and, where possible, an illustration of the tool will be provided so that an equivalent tool may be used.